“I do not see in their methodology any controls for cross-reactivity to other coronaviruses. If I were reviewing the paper, I’d ask for those kinds of controls.”
From post 45 (copied from the article).
In the below, where do you see cross reactivity with Non SARS-Cov-2 as an issue?
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The test kit used in this study (Premier Biotech, Minneapolis, MN) was tested in a Stanford laboratory
prior to field deployment. Among 37 samples of known PCR-positive COVID-19 patients with positive
IgG or IgM detected on a locally-developed ELISA test, 25 were kit-positive. A sample of 30 pre-COVID
samples from hip surgery patients were also tested, and all 30 were negative. The manufacturer’s test
characteristics relied on samples from clinically confirmed COVID-19 patients as positive gold standard
and pre-COVID sera for negative gold standard. Among 75 samples of clinically confirmed COVID-19
patients with positive IgG, 75 were kit-positive, and among 85 samples with positive IgM, 78 were kitpositive. Among 371 pre-COVID samples, 369 were negative. Our estimates of sensitivity based on the
manufacturer’s and locally tested data were 91.8% (using the lower estimate based on IgM, 95 CI 83.8-
96.6%) and 67.6% (95 CI 50.2-82.0%), respectively. Similarly, our estimates of specificity are 99.5% (95
CI 98.1-99.9%) and 100% (95 CI 90.5-100%). A combination of both data sources provides us with a
combined sensitivity of 80.3% (95 CI 72.1-87.0%) and a specificity of 99.5% (95 CI 98.3-99.9%).
The fact that they didn’t test for it at all is an issue. Coronavirus infection is pretty common this time of year.